The present invention relates generally to a contact-arm assembly having an electrical contact in an electrical circuit breaker. More specifically, the invention relates to a circuit breaker including a monolithic contact-arm structure and method of forming the same.
Contacts and contact arm assemblies are well known in the art of circuit breakers. Contact arm assemblies having electrical contacts for making and breaking an electrical current are not only employed in electrical circuit breakers, but also in other electrical devices, such as rotary double break circuit breakers, contactors, relays, switches, and disconnects.
The primary function of a contact-arm assembly is to provide an electrical current carrier that is capable of being actuated to separate the contact from a second contact, thereby enabling the making and breaking of an electrical current in an electric circuit.
The contact is generally bonded to the contact arm, which is typically, but not necessarily, a copper alloy. The contacts are generally joined to the arm by a brazing process using a braze alloy. Usage of braze alloy at the joining interface may lead to voids and defects at the interface. These process defects can act as heat pockets during an arcing event and become a primary reason for contact failure. Hence there is a need for improved joining of the contact and arm that can tolerate thermal, electrical and mechanical stresses, provide improved heat transfer between contact and arm, and improve the reliability of the assembly, during operation of the host device. The system and method presented herein are directed towards addressing this need.